1. Technical Field
The present invention relates to a ball joint and, in particular, to a seal for a ball joint.
2. Description of the Related Art
A typical ball joint includes a socket and a ball stud. The ball stud has a ball end portion received in the socket and a shank portion projecting from the ball stud. The socket supports the ball stud for pivotal movement relative to the socket with the shank portion extending from the socket. The ball joint also includes a seal that has a first end portion that seals against the socket. A second end portion of the seal seals against the shank portion of the ball stud. The seal prevents lubricant from coming out of the ball joint and also prevents dirt and other items from entering into the ball joint. The second end portion of the seal may wear against the ball stud, but still needs to be kept in sealing engagement.
The present invention is a ball joint comprising a socket defining a pivot center, a bearing in the socket, and a stud having a ball end portion received in the bearing and a shank portion projecting from the socket. The stud has a longitudinal axis extending through the pivot center. The bearing supports the stud in the socket for pivotal movement about the pivot center. The ball joint further comprises an annular seal having an intermediate portion extending between first and second end portions of the seal. The first end portion of the seal is fixed to the socket. The second end portion of the seal has an engagement portion in sealing engagement with the shank portion of the stud. The seal includes a spring molded in the second end portion of the seal and extending for 360 degrees around the circumference of the shank portion of the stud at a location radially outward of the engagement portion of the seal. The spring has a main body portion and a circular array of spring fingers that extend radially inward from the main body portion and exert a radially inward directed force on the engagement portion of the seal to maintain the engagement portion of the seal in sealing engagement with the shank portion of the stud.